4.4-stable review patch. If anyone has any objections, please let me know.
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From: Shubhrajyoti Datta shubhrajyoti.datta@xilinx.com
[ Upstream commit 03bc7cab7d7218088412a75e141696a89059ab00 ]
If the registration fails then mdio_unregister is called. However at unbind the unregister ia attempted again resulting in the below crash
[ 73.544038] kernel BUG at drivers/net/phy/mdio_bus.c:415! [ 73.549362] Internal error: Oops - BUG: 0 [#1] SMP [ 73.554127] Modules linked in: [ 73.557168] CPU: 0 PID: 2249 Comm: sh Not tainted 4.14.0 #183 [ 73.562895] Hardware name: xlnx,zynqmp (DT) [ 73.567062] task: ffffffc879e41180 task.stack: ffffff800cbe0000 [ 73.572973] PC is at mdiobus_unregister+0x84/0x88 [ 73.577656] LR is at axienet_mdio_teardown+0x18/0x30 [ 73.582601] pc : [<ffffff80085fa4cc>] lr : [<ffffff8008616858>] pstate: 20000145 [ 73.589981] sp : ffffff800cbe3c30 [ 73.593277] x29: ffffff800cbe3c30 x28: ffffffc879e41180 [ 73.598573] x27: ffffff8008a21000 x26: 0000000000000040 [ 73.603868] x25: 0000000000000124 x24: ffffffc879efe920 [ 73.609164] x23: 0000000000000060 x22: ffffffc879e02000 [ 73.614459] x21: ffffffc879e02800 x20: ffffffc87b0b8870 [ 73.619754] x19: ffffffc879e02800 x18: 000000000000025d [ 73.625050] x17: 0000007f9a719ad0 x16: ffffff8008195bd8 [ 73.630345] x15: 0000007f9a6b3d00 x14: 0000000000000010 [ 73.635640] x13: 74656e7265687465 x12: 0000000000000030 [ 73.640935] x11: 0000000000000030 x10: 0101010101010101 [ 73.646231] x9 : 241f394f42533300 x8 : ffffffc8799f6e98 [ 73.651526] x7 : ffffffc8799f6f18 x6 : ffffffc87b0ba318 [ 73.656822] x5 : ffffffc87b0ba498 x4 : 0000000000000000 [ 73.662117] x3 : 0000000000000000 x2 : 0000000000000008 [ 73.667412] x1 : 0000000000000004 x0 : ffffffc8799f4000 [ 73.672708] Process sh (pid: 2249, stack limit = 0xffffff800cbe0000)
Fix the same by making the bus NULL on unregister.
Signed-off-by: Shubhrajyoti Datta shubhrajyoti.datta@xilinx.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/ethernet/xilinx/xilinx_axienet_mdio.c | 1 + 1 file changed, 1 insertion(+)
--- a/drivers/net/ethernet/xilinx/xilinx_axienet_mdio.c +++ b/drivers/net/ethernet/xilinx/xilinx_axienet_mdio.c @@ -218,6 +218,7 @@ issue: ret = of_mdiobus_register(bus, np1); if (ret) { mdiobus_free(bus); + lp->mii_bus = NULL; return ret; } return 0;